The present invention relates to a high-density mounting multi-pin connector used for, e.g., a computer, an electronic exchange, and a data transmitter and, more particularly, to a surface-mounting connector to be connected to a printed board by surface mounting.
When a conventional connector of this type, e.g., a female connector, is designed to be arranged on a printed board, a large number of L-shaped female connector pins arranged parallel in two to four rows are used. More specifically, as shown in FIG. 6, in a female connector 81 arranged on a printed board 8, each L-shaped connector pin 82 is constituted by a metal spring. One end of each pin 82 is inserted/connected in/to a corresponding through hole 83 of the printed board 8 or is urged against a corresponding metal pad 84 typically consisting of a solder so as to be connected thereto by soldering, thus ensuring electrical connection with a circuit in the printed board 8.
The other end of each of the connector pins 82 is arranged in a corresponding pin insertion hole 85 of the female connector 81, whereas each rod-like male connector pin 88 of a male connector 87 arranged on a wiring board 86 is inserted in a corresponding insertion hole 85. With this arrangement, the two connectors 81 and 87 are set in a coupled state. Such a connector is disclosed in, e.g., Japanese Patent Laid-Open No. 59-49172.
If, however, such a connector is used for a high-speed logic apparatus such as a supercomputer and an ultra-high-speed wide-band electronic exchange, since each L-shaped female connector pin 82 has a long lead, high-frequency characteristics are adversely affected in terms of crosstalk amount, ground noise, delay time, and the like.
With an increase in number and density of pins of a connector, the distance between adjacent pads is reduced. In addition, wires of 100 .mu. width must be arranged between such adjacent pads at a pitch of about 300 .mu.. However, pitch errors at the printed board 8 side end portions, i.e., free ends, of the female connector pins 82 cannot be avoided. This makes it difficult to solder the connector pins to the metal pads arranged at a high density, and tends to develop short circuits between adjacent wires and in adjacent pads or cause connection failures. Moreover, since the pads respectively corresponding to a large number of connector pins are arranged on the printed board in the form of a matrix at a high density, it is very difficult to perform repair work once the above-mentioned short circuit or connection failure occurs.
That is, the drawbacks of the conventional connector are degradation in electric signal transmission characteristics due to the long leads of the connector pins 82 and poor assembly efficiency with respect to the printed board 8.